Electric switch



March 19, 1940, c. A. SCHAEFER 2,193,986

ELECTRIC SWITCH Filed Nov. 21, 1935 INVENTOR. Carl/Z Scfyae/en ATTORNEY.

Rwanda-19,19 2,193,986

UNITED STATES PATENT OFFICE ELECTRIC SWITCH Carl A. Schacfer, Detroit, Mich, assignor to Square D Company, Detroit, Mich a corporation of Michigan Application November 21, 1936, Serial No. 112,088

7 Claims. (01. 200-50) This invention relates to interconnected elecillustrating certain preferred embodiments of the trio switch combinations and more particularly invention in which: to an electric switch combination of manually. Figure 1 is a front elevational view of the and automatically operable switches providing switch combination according to the present in-. for simultaneous switch operation under certain vention with the cover removed and certain parts 5 conditions. broken away to show internal parts.

In the use of automatic electric switches re- Figure 2 is a partial vertical sectional view on sponsive to external'conditions it often becomes the line IIII of Figure 1.

desirable to maintain the switch in a definite The switch combination according to the presposition irrespective of the external condition in cut invention comprises an outer enclosing box 10 conjunction with the operation of associated de- I, provided with a removable cover, not shown, vices. One specific example of this is in the conwithin which are mounted a motor starting trol of ice cream cabinet motors wherein a hardswitch designated generally at 2 and a pressure ening cabinet and a freezer are provided with switch at 3. The motor starting switch correthe same compressor supplying the refrigerant sponds to that shown in the patent to H. L. Van 15 for the freezer and the cabinet. The pressure Valkenburg, et al., 1,912,109, granted May 30, switch is here normally responsive to the tem 1933, and comprises an insulating base 4 having perature of the hardening cabinet and it is demounted thereon a plurality of stationary consirable that when freezing the pressure switch be tact elements 5. Guided for rectilinear movemaintained in its closed position so that the comment at right angles to the base is an insulating 20 pressor motor will operate regardless of the cabyoke 6 carrying movable bridging contact eleinet temperature. This operation is in conjuncments 1. The switch is provided with a pair of tion with the operation of a freezer motor which push buttons 8 and 9 for'manually opening and stirs the batchto be frozen. closing the contacts and with overload relays One application of applicants invention is a indicated generally at H and |2 for automatiswitch combination wherein the starter switch cally opening the contacts in response to an overfor the freezer stirring motor is mechanically load through the switch, all as more fully decoupled with the automatic pressure switch rescribed and claimed in the aforesaid patent.

sponsive to the hardening cabinet temperature The pressure switch according to the present so that operation of the starter switch to initiate invention follows substantially 'the form de- 30 operation of the freezer motor will insure the scribed in applicants co-pending applications closing or maintaining closed of the pressure 77,723, filed May 4', 1936, for Electric switches and switch contacts whileflthe freezer motor is in 101,367, filed September 18, 1936, for Electric operation regardless of the hardening cabinet switches and comprises a pair of contact arms temperature. It is, of course, to be understood I3 and H with the arm l3 formed of magnetic 35 that this is only one of the many applicationsto material and having a limited relative movement which applicants invention is readily adaptable. with respect to the arm I4 which carries the One object of the invention is the combination movable contact IS. A permanent magnet |6 coofan electric switch controlling a translating deoperates with the magnetic arm l3 to effect a 40 vice with a switch automatically operable in requick make and break of the contacts as more 40 sponse to an external condition controlling a fully described in the aforesaid applications. A

second translating device, having provision for stationary contact I1 is movably mounted to vary insuring maintaining of the automatic switch in the differential of operation of the switch. The

a definite operating position irrespective of the arm l3 adjacent its lower portion is provided condition upon actuation of the first switch to with a pin I8 adapted to be engaged by an insuan-operating position. lating portion l9 rigid with a metallic lever 2| Another object of the invention is the combinahinged to a fixed part. The arm I4 is biased tion of a manually operable switch and a switch toward contacts engaged position by a spring 22 automatically operable in response to an external and is moved to disengaged position by engagecondition, having provision for insuring the 0105- ment of the portion |9 with the pin Is. For 50 ing of the automatic switch irrespective of the movingthe lever 2| there is provided a bellows condition when the manual switch is closed. chamber 23 having a bellows 24 therein to which Other objects and features will be readily apis connected a pin 25 bearing against the under parent to those skilled in the art from the folpart of the lever 2|. Bearing against the upper lowing specification and the appended drawing surface of the lever 2| is provided a compression 55 spring 26 engaged at its upper end by a nut 2'! threaded upon an adjusting screw 23 to provide adjustment of the range oi operation of the switch. Guided for vertical reciprocating movement by means of openings in the top and bottom of the pressure switch cover 'is a rod 29 biased in a downward direction by springs 3i and carrying a projection 32 engageable with the under side of the lever 2| to moveit to its upward position. The exterior end of the rod 29 is pivotally mounted to an operator 33 which, when moved downwardly, is adapted to pivot about the point 34 to move the rod 29 upwardly and through the projection 32 the lever 26 also. For moving the operator 33 there is provided a U-shaped bracket 35 rigidly mounted on the side walls of the outer enclosing box and within this bracket is guided a sliding member 36 biased in an upward direction by a spring 31. The lower end of the sliding member 36 is disposed to engage the operator 33 when the member is moved downwardly. Pivotally mounted on the side wall of the box is a bell crank lever 33 having an extension. 39 on one leg in the path of and adapted to be moved by a projection M on the insulating yoke 6 of the motor starting switch. The other leg of lever 38 is adapted to engage with and depress the member 35.

The operation of the device should be readily apparent from the above description. When the motor starter switch 2 is operated by pressing on the start push button 3 the yoke 6 will be moved downwardly and the projection 4! will ongage the extension 33 on the bell crank lever 38 and will rotate the bell crank in a clockwise direction as viewed in Figure 2. This will move the sliding member 36 in a downward direction and will thus depress the corresponding end of the operator 33 thus raising the rod 29 and through the projection 32 the lever 2| also, unless it was already in the upward position. This arrangement insures that the pressure switch contacts will always be in a desired operating position, which as here illustrated is closed, while the starting switch is in its closed position.

While certain preferred embodiments of the invention have been specifically disclosed, it is understood that the invention is not limited thereto as many variations will be readily apparent to those skilled in the art and the invention is to be given. its broadest possible interpretation within the terms of the following claims.

What is claimed is:

1. In a device of the class described, a pair of electrically independent electric switches, one

of said switches being automatically operable in response to an externalcondition, the other of said switches being manually operable at will,

and a mechanical connection between saidswitches whereby manual operation of said last mentioned switch to one operating position effects operation of said first mentioned switch to a definite operating position irrespective of said external condition.

2. In a device of the class described, a set of cooperating contacts automatically operable to open and closed positionsin response to an external condition, a second set of cooperating contacts manually operable to open and closed positions at will, and means for closing said first set of contacts irrespective of the condition when said second set of contacts is manually operated to closed position.

3. In a device of the class described, a motor starting switch, an electric switch automatically operable in response to an external condition and means operating in response to closing of the motor starting switch for holding the automatic switch closed irrespective of the nature of the external condition, said means positively moving the automatic switch to closed position if it should be open in response to the external condition when the motor starting switch is closed.

4. In a device of the class described. a manually operable electric switch for. controlling an electric translating device, an electric switch automatically operable in response to an external condition for controlling a second electric translating device, and mechanical connection between said switches for holding the automatic switch closed irrespective of the nature of the external condition when the manual switch is closed, said connection effecting the movement of the automatic switch to closed position if it should be open in response to the external condition when the manually operable switch is closed.

5. In a device of the class described, anelectric switch automatically operable in response to an external condition, including a switching lever, a member engageable with said lever to maintain it in contacts engaged position, a second electric switch, and mechanism movable by the closing of said second electric switch for moving position of the automatic switch if it should be in contacts disengaged position in response to the external. condition When the second electric switch is closed.

6. In a device of the class described, an electric switch .fcr controlling a translating device, an electric switch automatically operable in response to an external condition for controlling a second translating device and including a switching lever, a member engageable with said lever to maintain it in contacts engaged position, an operator connected to said member and adapted. to move it to lever engaging position when depressed, a member slidably mounted to engage said operator. a bell crank lever engaging said last mentioned member, and a part on said first mentioned electric switch engageable with said bell crank lever when moved to contacts engaged position to efiect movement of said parts and the maintaining or said automatic switch contacts in closed position irrespective of the external condition.

7. In a device of the class described, an outer enclosing box, a manual motor starting switch mounted in said box for controlling a translating device, an electric switch mounted in said box and automatically operable in response to an external condition for controlling a second translating device, a bell crank lever pivotally mounted on said box and having a part engagesble by said manually operable switch, a reciprocable member mounted on the box and having a part engageable by said bell crank lever, and

CARL A. SCHAEFER. 

